KR20210115411A - Controlling target temperature of fixing unit - Google Patents

Abstract

The fixing device may include a heating member, a pressing member forming the heating member and the fixing nip, a temperature sensor sensing the temperature of the first point of the heating member, and a processor. The processor sets a target temperature lower than a first set temperature at which normal fixing is possible for the entire area of the print medium when the distribution of images in the first area, which is a predetermined outer area of the print medium, is lower than a predetermined standard, Power supplied to the heating member may be controlled so that the temperature of the first point sensed by the temperature sensor becomes a set target temperature.

Description

Controlling the target temperature of the fixing unit {CONTROLLING TARGET TEMPERATURE OF FIXING UNIT}

An image forming apparatus such as a printer, a copier, or a multifunction machine transfers a print medium loaded in a loading unit to an image forming unit inside the image forming apparatus, forms a toner image on the print medium, and fixes the toner image to the print medium by passing it through a fixing unit. can do it When the fixing device maintains an appropriate temperature and pressure, the fixing level or fusing level of the toner can be maintained above a certain level. If the temperature of the fixing nip is too low, the toner cannot be properly fixed to the print media. If the temperature of the fixing nip is too high, the toner sticks to the rollers of the fixing unit. There has been interest in a method of controlling the amount of heat generated by the fixing unit in order to maintain the fixing performance of the toner above a certain level.

1 is a diagram for explaining a schematic structure and operation of an image forming apparatus.
2A and 2B are diagrams for explaining the relationship between the target temperature for controlling the amount of heat generated by the fixing unit and the fixing performance and energy efficiency performance of the fixing unit.
FIG. 3 is a view for explaining the temperature distribution characteristics of the fixing unit according to various target temperatures and the possibility of fixing in the area of the print medium.
4A and 4B are diagrams showing the area of the print medium by dividing it in order to explain the area of the print medium.
5 is a flowchart for explaining an example of controlling the temperature of the fixing unit.
6 is a flowchart for explaining another example of controlling the temperature of the fixing unit.
FIG. 7 is a view for explaining the possibility of fixing a portion of a heating member heated by each heat source in a fixing device including a plurality of heat sources, and a corresponding area and area of a print medium.
8A and 8B are diagrams showing the area of the print medium by dividing it in order to explain the area of the print medium.
9 is a flowchart illustrating an example of controlling the temperature of a fixing unit including a plurality of heat sources.
10 is a flowchart for explaining another example of controlling the temperature of the fixing unit including a plurality of heat sources.

Hereinafter, various embodiments will be described in detail with reference to the drawings. In addition, in the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and thus redundant descriptions will be omitted.

FIG. 1 is a diagram for explaining a schematic structure and operation of an image forming apparatus 100 . The image forming apparatus 100 according to the present embodiment may print a color image using an electrophotographic developing method.

The image forming apparatus 100 collectively refers to an apparatus capable of performing an image forming operation, such as a printer, a copier, a multifunction printer, and a fax machine. The image forming job may mean various jobs related to images, for example, printing, copying, or faxing, and may mean including a series of processes necessary for performing the image forming job. .

The developing device 10 may include a photosensitive member 14 on which an electrostatic latent image is formed, and a developing roller 13 that supplies a developer to the electrostatic latent image and develops a visible toner image. The photosensitive drum is an example of the photoconductor 14 and may be an organic photoconductor (OPC). The charging roller 15 is an example of a charger for charging the photosensitive member 14 to have a uniform surface potential. The developer accommodated in the developer cartridge (not shown) may be supplied to the developer 10 . The developer accommodated in the developer cartridge (not shown) may be toner.

The optical scanning device 50 scans the photosensitive member 14 with light modulated in response to image information to form an electrostatic latent image on the photosensitive member 14 , and a representative example thereof includes a laser scanning unit (LSU).

The transfer machine transfers the toner image formed on the photosensitive member 14 to the print medium P, and may be an intermediate transfer type transfer machine. As an example, the transfer machine may include an intermediate transfer body 60 , an intermediate transfer roller 61 , and a transfer roller 70 as shown in FIG. 1 . The intermediate transfer belt shown in FIG. 1 is an example of the intermediate transfer body 60 to which the developed toner image is transferred onto the photosensitive member 14 of each of the plurality of developing units 10, and can temporarily accommodate the toner image. . An intermediate transfer bias for intermediate transfer of the toner image developed on the photosensitive member 14 to the intermediate transfer member 60 may be applied to the plurality of intermediate transfer rollers 61 . The transfer roller 70 may be positioned to face the intermediate transfer body 60 .

The print medium P may be transferred along the paper feeding path R and transferred between the transfer roller 70 and the intermediate transfer body 60 . The toner image intermediately transferred onto the intermediate transfer member 60 by the transfer bias voltage applied to the transfer roller 70 may be transferred to the print medium P transferred between the transfer roller 70 and the intermediate transfer member 60 . have.

When the print medium P passes through the fixing unit 80, the toner image is fixed to the print medium P by heat and/or pressure. The shape of the heating member 81 for applying heat and the pressing member 85 for applying pressure may differ depending on the type of the fixing unit 80 . For example, the fixing unit 80 may be a 2-roll type, a 3-roll type, a Free Belt Nip Fuser (FBNF) type using a pressure belt with a built-in pressing unit, or IFS using a heating belt with a pressing unit. There may be an (Instantaneous Fusing System) type, an On-Demand Fusing (ODF) type, an Induction Heating (IH) type, or the like. The heating member 81 or the pressing member 85 may be in the form of a roller or a belt, depending on the type of the fixing unit 80 . The heating member 81 may be a single heat source or may include a plurality of heat sources, and the heat source may be a heating lamp or a ceramic heater. The fixed print medium P may be discharged by a discharge roller (not shown). The temperature sensor 89 may detect the temperature of the heating member 81 corresponding to the point at which the temperature sensor 89 is disposed, and the surface temperature or heating of the heating member 81 according to the type of the heating member 81 . It may be arranged to sense the temperature of the heat source in the member 81 . For example, since the temperature sensor 89 is expected that the temperature distribution of the heating member 81 may appear in a left-right symmetrical form based on the central portion of the heating member 81 , the surface or interior of the heating member 81 is It may be arranged to sense the temperature of a point corresponding to the central portion of the heat source, but is not limited thereto. The temperature sensor 89 may be disposed to sense the temperature of a predetermined point of the heating member 81 depending on the type of the fixing device 80 or the internal structure of the stationary device 80 . It may consist of a plurality of temperature sensors to check the temperature for each part of the .

According to the above configuration, the optical scanning device 50 scans the light modulated in response to image information of each color onto the photosensitive member 14 corresponding to each color, and provides the photosensitive member 14 with an electrostatic latent image corresponding to each color. can form. The electrostatic latent image of each photosensitive member 14 of the plurality of developers 10 can be developed into a visible toner image by the developer respectively supplied from the plurality of developer cartridges (not shown) to the plurality of developers 10 . The developed toner images are transferred to the intermediate transfer body 60 and then transferred back to the print medium P. When the print medium P passes through the fixing unit 80, the toner image is fixed to the print medium P. do.

2A and 2B are diagrams for explaining the relationship between the target temperature for controlling the amount of heat generated by the fixing unit 80 and the fixing performance and energy efficiency performance of the fixing unit 80 .

Referring to FIG. 2A , the printing medium P is transferred to the fixing nip formed by the heating member 81 and the pressing member 85 to fix the toner image formed on the printing medium P. Referring to FIG.

The heating member 81 and the pressing member 85 have a structure that rotates against each other, and the heating member 81 includes a heat source that generates heat along the longitudinal direction, which is the rotational axis direction. The amount of heat transferred to the toner image formed on the print medium P may be determined by the temperature of the heating member 81 . The heating member 81 has a different distribution of heat resistance in the longitudinal direction, and both end portions of the heating member 81 have lower heat resistance than the central portion. When the temperature of the heating member 81 is measured with respect to the entire length direction of the heating member 81 using a separate temperature measuring device, as shown in the temperature distribution diagram of FIG. 2A , both ends of the heating member 81 are It can be seen that the temperature is lower than that of the central part. Even if the temperature of the point X sensed by the temperature sensor 89 becomes a target temperature higher than the fixable temperature, as shown in FIG. 2A, the temperature of both ends of the heating member 81 is lower than the fixable temperature. can As a result, fixing failure may occur in the area of the print medium P corresponding to both end portions of the heating member 81 .

The fixable temperature means the minimum temperature required to perform fixation.

The target temperature means a temperature to which the temperature of a predetermined point sensed by the temperature sensor 89 of the fixing unit 80 must reach. The target temperature is a variable used to control the power supplied to the heating member 81, and the fixing unit 80 sets the temperature at the point X sensed by the temperature sensor 89 to the target temperature. 81) can be turned on or off. For example, the fixing unit 80 detects the temperature of a predetermined point of the surface of the central portion of the heating member 81 or a heat source in the heating member 81 with the temperature sensor 89, and when the corresponding point becomes the target temperature, Power can be supplied or cut off to the heating member 81 .

In the present disclosure, the target temperature may be set based on image information in a preset area of the print medium P, and may be set differently for each page of a print job target. For example, the target temperature may be set according to a result of comparing the image distribution in the predetermined outer region of the print medium P with a predetermined reference. The distribution of images in a certain area means the degree to which images to be printed are distributed in the corresponding area, and may be a measure of whether the amount of images to be printed in the corresponding area is large or small. When there is no image to be printed in the preset area of the print medium P or is less than a predetermined standard, the target temperature may be set lower than when there is an image to be printed in the preset area or higher than the predetermined reference. In other words, the lower the distribution of images in the preset area of the print medium P, the lower the target temperature may be set.

According to the distribution of thermal resistance in the longitudinal direction of the heating element 81 , the temperature distribution of the heating element 81 is sensed by the temperature sensor 89 at both ends of the heating element 81 , as shown in FIG. 2A . It can be seen that the temperature is lower than that of the central part, which is the point (X). Therefore, in order for normal fixation to be possible for the entire area in the width direction of the printing medium P corresponding to the longitudinal direction of the heating member 81, considering the characteristics of low temperatures at both ends of the heating member 81, the target It is necessary to set the temperature higher.

As an example, referring to FIG. 2B , by setting the target temperature to which the temperature of the point X sensed by the temperature sensor 89 should reach higher than that of FIG. 2A , corresponding to the longitudinal direction of the heating member 81 It can be seen that the temperature at which normal fixing is possible is maintained for the entire area in the width direction of the print medium P.

Accordingly, if the target temperature of the fixing unit 80 is set high, fixing failure does not occur in the entire area of the print medium P in the width direction, and fixing performance can be improved. However, when comparing the case of FIG. 2A and the case of FIG. 2B in terms of energy efficiency performance, it can be seen that in the case of FIG. 2B , power consumption increases, energy loss increases, and energy efficiency performance decreases. That is, the higher the target temperature used to control the power supplied to the heating member 81 for heat generation of the heating member 81, the higher the fixing performance of the fixing device 80, while the energy efficiency performance is lowered, It can be seen that there is a trade-off relationship.

3 is a view for explaining the temperature distribution characteristics of the fixing unit 80 according to various target temperatures and the possibility of fixing the area of the print medium P. Referring to FIG.

Referring to FIG. 3 , the fixing device 80 includes a heating member 81 including one heat source 83 , a pressing member 85 forming a fixing nip with the heating member 81 , and a first heating member 81 . It may include a temperature sensor 89 for sensing the temperature of one point. It can be seen that the amount of heat transferred from the heating member 81 to the print medium P passing through the fixing nip of the fixing unit 80 may vary depending on the temperature distribution characteristic of the heating member 81 .

As shown in FIG. 3 , when the target temperature is each of the first temperature FT, the second temperature ST, and the third temperature TT, the first temperature distribution diagram and the second temperature respectively corresponding thereto The distribution diagram and the third temperature distribution diagram are compared with each other as follows.

When the target temperature is the first temperature FT, since the first temperature distribution for the entire area of the print medium P is above the fixable temperature, it can be seen that there is no area in the print medium P where fixing failure may occur. can However, when the target temperature is lowered to the second temperature ST, the second temperature distribution for some regions of both ends in the width direction of the printing medium P is lower than the fixable temperature, so the There is a possibility that fixing failure may occur in some areas of area 1. When the target temperature is lowered to the third temperature TT, the third temperature distribution is lower than the fixable temperature for the first area at both ends in the width direction of the print medium P, Fixing failure may occur in area 1. On the other hand, comparing the first energy loss at the first temperature FT, the second energy loss at the second temperature ST, and the third energy loss at the third temperature TT, as the target temperature decreases, It can be seen that the energy loss is also reduced.

Therefore, it is important to adjust the performance of the fixing unit 80 by setting a target temperature for each page of the print job so as to reduce the energy loss while maintaining the fixing performance.

A processor (not shown) of the fixing unit 80 may supply power to the heating member 81 based on a first set temperature at which normal fixing is possible for the entire area of the print medium P according to a print job command. The first set temperature is a temperature of a predetermined point of the heating member 81 for normal fixing to the entire area of the print medium P, and in order to improve fixability of both ends of the fixing unit 80, in advance It may be a value measured in advance. The first set temperature is a temperature that enables normal fixing to the entire area of the printing medium P, and is normal for the entire area in the width direction of the printing medium P corresponding to the longitudinal direction of the heating member 81. It may be the lowest temperature that can ensure fixation. The first set temperature may be pre-stored as a specific temperature value in a memory (not shown), and the processor (not shown) of the fixing unit 80 is pre-stored in the memory (not shown) according to a print job command. Power supplied to the heating member 81 may be controlled with reference to the first set temperature. The first set temperature may be the lowest temperature among temperatures that can ensure normal fixation for the entire area of the print medium P, and the value may be changed according to a setting of a user or an administrator. However, according to the print job command, the process of supplying power to the heating member 81 based on the first set temperature may be performed before setting the target temperature for the first page of the print job or may be omitted. .

A processor (not shown) of the fixing unit 80 may set a target temperature equal to or less than the first set temperature based on image information on the first area, which is a predetermined outer area of the print medium P. The processor (not shown) of the fixing unit 80 may set a target temperature lower than the first set temperature when the distribution of images in the first area of the print medium P is lower than a predetermined reference. For example, the processor (not shown) of the fixing unit 80 may set the target temperature to be lower as the distribution of images in the first region is lower. A processor (not shown) of the fixing unit 80 may control the power supplied to the heating member 81 so that the temperature of the first point sensed by the temperature sensor 89 becomes a set target temperature.

Depending on the temperature raising performance of the fixing unit 80 or the data processing performance of the processor (not shown), the target temperature may be set before the temperature of the first point sensed by the temperature sensor 89 reaches the first set temperature. have. The processor (not shown) of the fixing unit 80 sets a target temperature lower than the first set temperature before the temperature of the first point sensed by the temperature sensor 89 reaches the first set temperature, the temperature sensor Power supplied to the heating member 81 may be controlled so that the temperature sensed by 89 becomes a set target temperature without reaching the first set temperature. According to this, the temperature of the heating member 81 is not increased so that the temperature of the first point sensed by the temperature sensor 89 reaches the first set temperature, but is heated to a target temperature that is lower than the first set temperature. By controlling the power supplied to the member 81, it is possible to reduce the FPOT (Fit Page Out Time), reduce the occurrence of curl of the print medium P, and reduce energy loss.

4A and 4B are diagrams illustrating the area of the print medium P by dividing the area of the print medium P. Referring to FIG.

The target temperature for each page of the print job object may be set based on image information on a predetermined outer region of the print medium P. In this case, examples of FIGS. 4A and 4B will be described in relation to how to define the outer region, but the present invention is not limited thereto.

4A is an example in which the area of the print medium P corresponding to both end portions of the heating member 81 is used as the outer area in consideration of the temperature distribution characteristics of the heating member 81 . Referring to FIG. 4A , the print medium P may be divided into a first area corresponding to a predetermined outer area and a second area corresponding to a central area.

On the other hand, the leading and trailing regions, which are regions within the first range from each of the leading edge and trailing edge in the conveying direction of the print medium P, tend to have lower fixability than the central region between the front and trailing regions. In particular, when the print medium P of various basis weights is supported by the image forming apparatus 100 due to the size or material of the print medium P, the front end area and the rear end area are fixed according to the basis weight of the print medium P. There is a case where the stamina goes down. In this case, the outer area of the print medium P shown in FIG. 4B may be used as the first area. The first area of FIG. 4b includes an area within the first range from each of the leading edge and the trailing edge in the transport direction of the print medium P and the area within the second range from both edges in the width direction of the print medium P. Able to know.

5 is a flowchart for explaining an example of controlling the temperature of the fixing unit 80 .

In block 505, the fixing unit 80 may supply power to the heating member 81 based on a first set temperature at which normal fixing is possible for the entire area of the print medium P. The fixing unit 80 may supply power to the heating member 81 based on a first set temperature at which normal fixing is possible for the entire area in the width direction of the print medium corresponding to the length direction of the heating member 81 . However, such a process is not necessarily performed, and may be applied as a preceding process if necessary.

In block 510 , the fixing unit 80 may acquire image information about a first area that is a predetermined outer area of the print medium P. For example, the fixing unit 80 may acquire image information about the first area within a predetermined range from both edges of the print medium P in the width direction.

In block 515 , the fixing unit 80 may determine whether there is an image for the first area.

In block 520 , the fixing unit 80 may set the target temperature as the first target temperature if there is an image for the first area. The first target temperature is equal to or less than the first set temperature.

In block 525 , the fixing unit 80 may set the target temperature to a second target temperature lower than the first target temperature if there is no image for the first area.

In block 530 , the fixing unit 80 may control the power supplied to the heating member 81 such that the temperature of the first point sensed by the temperature sensor 89 becomes a set target temperature.

In block 535, the fuser 80 may determine whether there is a next page to be printed. If there is a next page to be worked on, the process may proceed to block 510 to resume the target temperature control process for the next page, and if there is no next page to be printed, the print job may be terminated. The fixing unit 80 may perform a process of controlling the target temperature of blocks 510 to 530 for each page of the print job.

Table 1 below shows the target temperature according to the presence or absence of an image in the first area, and the difference between the FPOT and the fusing power consumption accordingly. When there is no image for the first area, in preparation for the case where there is an image for the first area, the target temperature can be set lower by 8°C, thereby reducing the FPOT by 9.5% and reducing the fusing power consumption by 3.1% can be known

for the first area
If you have burns for the second area
If there is no burn note Target temperature (℃) 181 173 8℃ reduction FPOT(sec) 17.48 15.82 9.5% reduction Fusing power consumption (wh) 415.5 402.5 3.1% reduction

6 is a flowchart for explaining another example of controlling the temperature of the fixing unit 80 .

In block 605 , the fixing unit 80 may supply power to the heating member 81 based on a first set temperature at which normal fixing is possible for the entire area of the print medium P. The fixing unit 80 may supply power to the heating member 81 based on the first set temperature at which normal fixing is possible for the entire area in the width direction of the print medium P corresponding to the length direction of the heating member 81 . have. However, such a process is not necessarily performed, and may be applied as a preceding process if necessary.

In block 610 , the fixing unit 80 may acquire image information about the first area. The fixing unit 80 may acquire image information for the first area within a predetermined range from both edges of the print medium P in the width direction. The fixing unit 80 may acquire image information of print data for each area of the print medium P. The fixing unit 80 may acquire image information on the second region as well as image information on the first region of FIG. 4A or 4B .

In block 615 , the fixing unit 80 may determine whether there is an image for the first area.

In block 620, when there is an image for the first region, the fixing unit 80 determines whether the coverage of the image for the first region of the print medium P is equal to or greater than the first reference value or the image for the first region is only text. It can be determined whether or not The coverage of an image is a numerical value indicating how much toner is consumed in a corresponding area, and may be determined by the number of pixels or dots of the image for the corresponding area. The first reference value may be a preset value, and the value may be changed by a user or an administrator.

In block 625 , the fixing unit 80 sets the target temperature to the first set temperature if the coverage of the image for the first area of the print medium P is equal to or greater than the first reference value or the image for the first area is not made of only text. The following third target temperature may be set.

In block 630 , the fixing unit 80 sets the target temperature lower than the third target temperature when the coverage of the image for the first region of the print medium P is less than the first reference value or the image for the first region consists of only text. The fourth target temperature may be set.

In block 635 , when there is no image for the first area, the fixing unit 80 determines that the coverage of the image for the second area excluding the first area in the entire area of the print medium P is equal to or greater than the second reference value or the second area. It can be determined whether the image for . The second reference value may be a preset value, and the value may be changed by a user or an administrator.

In block 640 , the fixing unit 80 sets the target temperature to the fifth target temperature when the coverage of the image for the second region of the print medium P is equal to or greater than the second reference value or the image for the second region is not composed of only text. can be set to

In block 645 , the fixing unit 80 sets the target temperature to the fourth target temperature and the second target temperature when the coverage of the image for the second region of the print medium P is less than the second reference value or the image for the second region consists only of text. A sixth target temperature lower than the 5 target temperature may be set.

In block 650 , the fixing unit 80 may control the power supplied to the heating member 81 such that the temperature of the first point sensed by the temperature sensor 89 becomes a set target temperature.

In block 655, the fuser 80 may determine whether there is a next page to be printed. If there is a next page to be worked on, the process may proceed to block 610 to resume the target temperature control process for the next page, and if there is no next page to be printed, the print job may be terminated. The fixing unit 80 may perform a process of controlling a target temperature of blocks 610 to 650 for each page of a print job.

7 is a view for explaining the possibility of fixing the area of the heating member 81 heated by each heat source in the fixing unit 80 including a plurality of heat sources and the area and area of the print medium P corresponding thereto; am.

The heating member 81 of the fixing unit 80 may include a plurality of heat sources. As shown in FIG. 7 , the heating member 81 includes a first heat source 83-1 for heating both end portions of the heating member 81 and a second heat source 83-2 for heating a central portion between the opposite end portions of the heating member 81 . may include. The first temperature sensor 89 - 1 may sense the temperature of any one of the two end portions of the both ends of the heating member 81 , and the second temperature sensor 89 - 2 is the central portion of the heating member 81 . It is possible to detect the temperature of the third point of

The print medium P has a fifth region fixed by the central portion of the heating member 81 heated by the second heat source 83-2 and the heating member 81 heated by the first heat source 83-1. It may include a third region and a fourth region fixed by both end portions of the.

According to the fixing device 80 including a plurality of heat sources as shown in FIG. 7 , the fifth region fixed by the central portion of the heating member 81 is subject to the central portion target temperature TC control by the second heat source 83-2. Heat may be applied accordingly, and the third region and the fourth region fixed by both end portions of the heating member 81 may be heated according to the end target temperature TS control by the first heat source 83-1. have.

The central target temperature TC means a temperature to which the temperature of the third point sensed by the second temperature sensor 89 - 2 of the fixing unit 80 must reach. The central target temperature TC is a variable used to control the power supplied to the second heat source 83 - 2 , and the fixing unit 80 determines the central target temperature of the temperature sensed by the second temperature sensor 89 - 2 . (TC), it is possible to supply or cut off the power to the second heat source (83-2). For example, the fixing unit 80 detects the temperature of the surface of the central portion of the heating member 81 or the temperature of the third point of the heat source in the central portion with the second temperature sensor 89-1, while the third point is the central portion target temperature ( TC), power may be supplied or cut off to the second heat source 83-2.

The distal end target temperature TS means a temperature to which the temperature of the second point sensed by the first temperature sensor 89 - 1 of the fixing unit 80 must reach. The distal end target temperature TS is a variable used to control the power supplied to the first heat source 83 - 1 , and the fixing unit 80 determines that the temperature sensed by the first temperature sensor 89 - 1 is the distal end target temperature. (TS), power may be supplied or cut off to the first heat source 83 - 1 . For example, the fixing unit 80 detects the temperature of the second point of the heat source in the surface or both end portions of the both end portions of the heating member 81 with the first temperature sensor 89-1, while the second point is the distal end target. Power may be supplied or cut off to the first heat source 83 - 1 until the temperature TS is reached.

The temperature of both end portions of the heating member 81 may be lower at the outer side than the inner side toward the central portion of the heating member 81 . As a result, as previously shown in FIG. 2A , the temperature of a portion of both end portions of the heating member 81 is lower than the fixable temperature, so that fixing failure may occur in the outer region of the print medium P. That is, fixing failure may occur in the third area among the areas of the print medium P fixed by both end portions of the heating member 81 heated by the first heat source 83 - 1 .

In order to solve this, by setting higher the distal end target temperature TS used to control the first heat source 83-1 for controlling the amount of heat generated at both end portions of the heating member 81, both sides of the heating member 81 are set higher. Normal fixing may be possible for the third area and the fourth area of the print medium P corresponding to the distal end. However, it is important to adjust the performance of the fixing unit 80 by setting a target end temperature TS for each page of the print job so as to reduce the energy loss while maintaining the fixing performance.

The processor (not shown) of the fixing unit 80 may supply power to the first heat source 83-1 based on a second set temperature at which normal fixing is possible for the third area and the fourth area according to a print job command. have. The second set temperature may be the lowest temperature that can ensure normal fixation in the third and fourth regions of the print medium P corresponding to both end portions of the heating member 81 . The second set temperature may be pre-stored as a specific temperature value in a memory (not shown), and the processor (not shown) of the fixing unit 80 is pre-stored in the memory (not shown) according to a print job command. Power supplied to the first heat source 83 - 1 may be controlled with reference to the second set temperature.

The processor (not shown) of the fixing unit 80 may set the target end temperature TS lower than the second set temperature when the distribution of the image for the third region, which is an outer region than the fourth region, is lower than a predetermined reference. . The processor (not shown) of the fixing unit 80 is supplied to the first heat source 83-1 so that the temperature of the second point sensed by the first temperature sensor 89-1 becomes the set end target temperature TS. Power can be controlled.

The processor (not shown) of the fixing unit 80 sets the end target temperature TS lower than the second set temperature before the temperature of the second point sensed by the first temperature sensor 89-1 reaches the second set temperature. ) is set, the first heat source 83- so that the temperature of the second point sensed by the first temperature sensor 89-1 becomes the set end target temperature TS without reaching the second set temperature. The power supplied to 1) can be controlled. According to this, the temperature of both ends of the heating member 81 is not increased so that the temperature of the second point sensed by the first temperature sensor 89-1 reaches the second set temperature, and is lower than the second set temperature. By controlling the power supplied to the first heat source 83-1 so that the temperature, which is the end target temperature TS, is controlled, the FPOT can be reduced, the curling of the print medium P can be reduced, and the energy loss can be reduced. .

On the other hand, for each page of the print job target, in order to control the central target temperature (TC), the processor (not shown) of the fixing unit 80 sets a third setting in which normal fixing is possible for the fifth area according to the print job command. Power may be supplied to the second heat source 83 - 2 based on the temperature. The third set temperature may be the lowest temperature that can ensure normal fixation of the fifth area of the print medium P corresponding to the central portion of the heating member 81 . The third set temperature may be pre-stored as a specific temperature value in a memory (not shown), and the processor (not shown) of the fixing unit 80 is pre-stored in the memory (not shown) according to a print job command. Power supplied to the second heat source 83 - 2 may be controlled with reference to the third set temperature. The processor (not shown) of the fixing unit 80 sets the central target temperature TC lower than the third set temperature when the distribution of the image for the fifth region is lower than the predetermined reference, and the second temperature sensor 89- The power supplied to the second heat source 83-2 may be controlled so that the temperature of the third point sensed by 2) becomes the set central target temperature TC.

8A and 8B are diagrams for dividing the area of the print medium P in order to explain the area of the print medium P. Referring to FIG.

The end target temperature TS and the central target temperature TC for each page of the print job object may be set based on image information for each area of the print medium P. The end target temperature TS may be set based on image information for the third region and the fourth region of the print medium P. The lower the distribution of the image in the third region, the lower the end target temperature TS may be set. The central part target temperature TC may be set based on image information about the fifth area of the print medium P. The lower the distribution of the image in the fifth region, the lower the central target temperature TC may be set.

8A, in consideration of the temperature distribution characteristic of the heating member 81, in the region of the print medium P corresponding to both end portions of the heating member 81, the outer region is the third region, and the remainder is the fourth region. is an example of Compared to the third area of FIG. 8A , the third area of FIG. 8B has a leading edge and a trailing edge in the transport direction of the printing medium P within the area of the printing medium P corresponding to both end portions of the heating member 81 , compared to the third area of FIG. 8A . It can be seen that the form further includes a region within a predetermined range from each.

9 is a flowchart illustrating an example of controlling the temperature of the fixing unit 80 including a plurality of heat sources.

In block 905, the fixing unit 80 supplies power to the first heat source 83-1 based on the second set temperature at which normal fixing is possible for the third region and the fourth region, and normal fixing for the fifth region Power may be supplied to the second heat source 83 - 2 based on the third possible set temperature. The fixing device 80 includes the heating member 81 based on the second set temperature and the third set temperature at which normal fixing is possible for the entire area in the width direction of the print medium P corresponding to the longitudinal direction of the heating member 81 . can supply power to The fixing unit 80 is provided to a first heat source 83-1 for heating both end portions in the longitudinal direction of the heating member 81 and a second heat source 83-2 for heating a central portion between both end portions at a second set temperature, respectively. and power corresponding to the third set temperature may be supplied, respectively. However, such a process is not necessarily performed, and may be applied as a preceding process if necessary.

In block 910 , the fixing unit 80 may acquire image information for each area of the print medium P. For example, the fixing unit 80 may obtain image information for each of the third area, the fourth area, and the fifth area of the print medium P of FIG. 8A or 8B . Thereafter, the fixing unit 80 independently performs a process for controlling the distal end target temperature TS (corresponding to blocks 935 to 960) and a process for controlling the central portion target temperature TC (corresponding to blocks 915 to 930) independently, respectively. can proceed.

In block 915 , the fixing unit 80 may determine whether there is an image for the fifth area of the print medium P.

In block 920 , the fixing unit 80 may set the central target temperature TC as the first central target temperature when there is an image for the fifth region of the print medium P. The first central portion target temperature is equal to or less than the second set temperature.

In block 925 , if there is no image for the fifth region of the print medium P, the central part target temperature TC may be set to a second central part target temperature lower than the first central part target temperature.

In block 930, the fixing unit 80 applies the power supplied to the second heat source 83-2 so that the temperature of the third point sensed by the second temperature sensor 89-2 becomes the set central target temperature TC. can be controlled

Meanwhile, the processes of blocks 915 to 930 of controlling the central part target temperature TC may be modified and performed according to another example. In an example different from the example shown in FIG. 9, the fixing unit 80, for each page of the print job, in the fifth area, a leading edge within a predetermined range from a leading edge and a trailing edge in the transport direction of the print medium P. If there is an image for the region and the trailing region, the central part target temperature (TC) is set as the sixth central part target temperature. The power supplied to the second heat source 83-2 is set to the seventh central part target temperature, and the temperature of the third point sensed by the second temperature sensor 89-2 becomes the set central part target temperature TC. can be controlled

As another example, the fixing unit 80 controls the power supplied to the second heat source 83-2 by setting the central target temperature TC to a predetermined temperature regardless of the image information of the print medium P. And, only the process of controlling the end target temperature TS may set the end target temperature TS based on image information of the print medium P to control the power supplied to the first heat source 83-1 have.

Referring back to FIG. 9 , in block 935 , the fixing unit 80 may determine whether there is an image for the third area of the print medium P.

In block 940 , when there is an image for the third region of the print medium P, the fuser 80 may set the distal end target temperature TS as the first distal end target temperature. The first end target temperature is equal to or less than the third set temperature.

In block 945 , when there is no image for the third area of the print medium P, the fixing unit 80 may determine whether there is an image for the fourth area.

In block 950 , if there is an image for the fourth region of the print medium P, the end target temperature TS may be set to a second end target temperature lower than the first end target temperature.

In block 955 , the fuser 80 may set the target tip temperature TS to a third target temperature lower than the second target temperature if there is no image for the fourth region of the print medium P.

In block 960 , the fixing unit 80 may control the power supplied to the first heat source 83-1 so that the temperature sensed by the first temperature sensor 89-1 becomes the set end target temperature TS. .

In block 965 , the fuser 80 may determine whether there is a next page to be printed. If there is a next page to be worked on, proceed to block 910 where the process of controlling the tip target temperature (TS) and the process controlling the central target temperature (TC) for the next page are independently resumed, and the next page to be printed If there are no pages, the print job may end. The fusing unit 80 includes a process for controlling a tip target temperature TS (corresponding to blocks 935 to 960) and a process for controlling a center target temperature TC (corresponding to blocks 915 to block 930) for each page of the print job object. ) can be performed independently of each other.

10 is a flowchart for explaining another example of controlling the temperature of the fixing unit 80 including a plurality of heat sources.

In block 1005, the fixing unit 80 supplies power to the first heat source 83-1 based on the second set temperature at which normal fixing is possible for the third region and the fourth region, and normal fixing for the fifth region. Power may be supplied to the second heat source 83 - 2 based on the third possible set temperature. The fixing device 80 includes the heating member 81 based on the second set temperature and the third set temperature at which normal fixing is possible for the entire area in the width direction of the print medium P corresponding to the longitudinal direction of the heating member 81 . can supply power to The fixing unit 80 is provided to a first heat source 83-1 for heating both end portions in the longitudinal direction of the heating member 81 and a third heat source 83-3 for heating a central portion between both end portions at a second set temperature, respectively. and power corresponding to the third set temperature may be supplied, respectively. However, such a process is not necessarily performed, and may be applied as a preceding process if necessary.

In block 1010 , the fixing unit 80 may acquire image information for each area of the print medium P. For example, the fixing unit 80 may obtain image information for each of the third area, the fourth area, and the fifth area of the print medium P of FIG. 8A or 8B . Thereafter, the fixing unit 80 independently performs a process for controlling the distal end target temperature TS (corresponding to blocks 1045 to 1090) and a process for controlling the central portion target temperature TC (corresponding to blocks 1015 to 1040) independently, respectively. can proceed.

In block 1015 , the fixing unit 80 may determine whether the fixing unit 80 has an image for the fifth area.

In block 1020 , when there is an image for the fifth region, the fixing unit 80 may determine whether the coverage of the image for the fifth region is equal to or greater than a third reference value or the image for the fifth region is not composed of only text. . The third reference value may be a preset value, and the value may be changed by a user or an administrator.

In block 1025, if the coverage of the image for the fifth region of the print medium P is equal to or greater than the third reference value or the image for the fifth region does not consist of only text, the fixing unit 80 sets the central target temperature TC. It can be set as the target temperature of the third central part. The third central portion target temperature is equal to or less than the third set temperature.

In block 1030, if the coverage of the image for the fifth region of the print medium P is less than the third reference value or the image for the fifth region consists only of text, the fixing unit 80 sets the central target temperature TC to the third The fourth central part target temperature TC3 lower than the central part target temperature may be set.

In block 1035 , when there is no image for the fifth region of the print medium P, the fixing unit 80 may set the central part target temperature TC to a fifth central part target temperature lower than the fourth central part target temperature.

In block 1040, the fixing unit 80 applies the power supplied to the second heat source 83-2 so that the temperature of the third point sensed by the second temperature sensor 89-2 becomes the set central target temperature TC. can be controlled

Meanwhile, the processes of blocks 1015 to 1040 of controlling the central portion target temperature TC may be modified and performed according to another example. For example different from the example shown in FIG. 10 , the fixing unit 80, for each page of the print job, in the fifth area, a leading edge within a predetermined range from a leading edge and a trailing edge in the transport direction of the print medium P. If there are images for the region and the trailing area, if the coverage of the images for the leading and trailing regions is equal to or greater than the sixth reference value, or if the images for the leading and trailing regions do not consist of text only, the central target temperature (TC) If the eighth central part target temperature below the third set temperature is set, and the central part target temperature TC is lower than the eighth central part target temperature, if it is less than the sixth reference value or the images for the leading and trailing regions consist only of text. It can be set as the central target temperature. In the fifth area, when there is no image for the front end area and the rear end area, the fixing unit 80 determines that the coverage of the image for the central area between the front end area and the rear end area in the fifth area is equal to or greater than the seventh reference value or the image for the center area. If the text is not the only text, the central part target temperature TC is set as the 10th central part target temperature, and if the central part target temperature TC is less than the seventh reference value or if the image for the central region consists of only text, the central part target temperature TC is set to the ninth central part target temperature. The eleventh central part target temperature lower than the target temperature and the tenth central part target temperature may be set. The fixing unit 80 may control the power supplied to the second heat source 89-2 so that the temperature of the third point sensed by the second temperature sensor 89-2 becomes the set central target temperature TC. .

As another example, the fixing unit 80 controls the power supplied to the second heat source 83-2 by setting the central target temperature TC to a predetermined temperature regardless of the image information of the print medium P. And, only the process of controlling the end target temperature TS may set the end target temperature TS based on image information of the print medium P to control the power supplied to the first heat source 83-1 have.

Referring back to FIG. 10 , in block 1045 , the fixing unit 80 may determine whether there is an image for the third area of the print medium P.

In block 1050, when there is an image for the third region of the print medium P, the fixing unit 80 determines whether the coverage of the image for the third region is equal to or greater than the fourth reference value or the image for the third region is only text. It can be determined whether or not The fourth reference value may be a preset value, and the value may be changed by a user or an administrator.

In block 1055, if the coverage of the image for the third region of the print medium P is equal to or greater than the fourth reference value or the image for the third region does not consist of only text, the fuser 80 sets the end target temperature TS. It may be set to a target temperature of the fourth end of the second set temperature or less.

In block 1060, if the coverage of the image for the third region of the print medium P is less than the fourth reference value or the image for the third region consists only of text, the fixing unit 80 sets the target end temperature TS as the fourth A fifth end target temperature lower than the end end target temperature may be set.

In block 1065 , when there is no image for the third area of the print medium P, the fixing unit 80 may determine whether there is an image for the fourth area.

In block 1070, when there is an image for the fourth region of the print medium P, the fixing unit 80 determines whether the coverage of the image for the fourth region is equal to or greater than the fifth reference value or the image for the fourth region is only text. It can be determined whether or not The fifth reference value may be a preset value, and the value may be changed by a user or an administrator.

In block 1075, if the coverage of the image for the fourth region of the print medium P is equal to or greater than the fifth reference value or the image for the fourth region does not consist only of text, the fuser 80 sets the target end temperature TS. The sixth end portion may be set to a target temperature.

In block 1080, if the coverage of the image for the fourth region of the print medium P is less than the fifth reference value or the image for the fourth region consists only of text, the fixing unit 80 sets the end target temperature TS to the sixth The seventh end end target temperature TS5 lower than the end end target temperature may be set.

In block 1085 , the fixing unit 80 sets the end target temperature TS to an eighth end target temperature lower than the seventh end target temperature when there are no images for the third region and the fourth region of the print medium P. can

In block 1090, the fixing unit 80 applies the power supplied to the first heat source 83-1 so that the temperature of the second point sensed by the first temperature sensor 89-2 becomes the set end target temperature TS. can be controlled

In block 1095, the fuser 80 may determine whether there is a next page to be printed. If there is a next page to be worked on, it proceeds to block 1010 where the process of controlling the tip target temperature (TS) and the process controlling the central target temperature (TC) for the next page are independently resumed, and the next page to be printed If there are no pages, the print job may end. The fusing unit 80 includes a process for controlling the tip target temperature TS (corresponding to blocks 1045 to 1090) and a process for controlling the center target temperature TC (corresponding to blocks 1015 to block 1040) for each page of the print job object. ) can be performed independently of each other.

Meanwhile, the method of controlling the temperature of the fixing unit 80 described above may be implemented in the form of a computer-readable storage medium storing instructions executable by a computer or processor. It can be written as a program that can be executed on a computer, and can be implemented in a general-purpose digital computer that operates such a program using a computer-readable storage medium. Such computer-readable storage media include read-only memory (ROM), random-access memory (RAM), flash memory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs, DVD-ROMs. , DVD-Rs, DVD+Rs, DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs, BD-REs, magnetic tapes, floppy disks, magneto-optical data storage devices, optical data storage devices, hard disks, solid-state disks (SSDs), and may store instructions or software, related data, data files, and data structures, and may store instructions or It can be any device capable of providing software, associated data, data files, and data structures.

Claims (15)

heating element;
a pressing member forming the heating member and the fixing nip;
a temperature sensor for sensing the temperature of the first point of the heating member; and
When the distribution of images in the first area, which is a predetermined outer area of the print medium, is lower than a predetermined reference, a target temperature lower than a first set temperature at which normal fixing is possible is set for the entire area of the print medium, and the temperature sensor a processor for controlling the power supplied to the heating member so that the temperature of the first point sensed by the target temperature becomes the set target temperature;
A fixing device comprising a. The method of claim 1,
The processor is
and setting the target temperature to be lower as the distribution of the image in the first region is lower. The method of claim 1,
The processor is
According to a print job command, after supplying power to the heating member based on the first set temperature, the target temperature is set to control the power supplied to the heating member. The method of claim 1,
The processor is
When there is an image for the first region, the target temperature is set as a first target temperature, and when there is no image for the first region, the target temperature is set to a second target temperature lower than the first target temperature to set, the fuser unit. The method of claim 1,
The processor, if there is an image for the first area,
If the coverage of the image for the first region is equal to or greater than the first reference value or the image for the first region is not composed of only text, the target temperature is set as a third target temperature,
setting the target temperature to a fourth target temperature lower than the third target temperature when the coverage of the image for the first area is less than the first reference value or when the image for the first area consists only of text. The method of claim 1,
The processor is
If there is no image for the first area,
If the coverage of the image for the second area excluding the first area in the entire area of the print medium is equal to or greater than the second reference value or if the image for the second area does not consist of only text, the target temperature is set to the fifth target temperature set to,
setting the target temperature to a sixth target temperature lower than the fifth target temperature when the coverage of the image for the second region is less than the second reference value or when the image for the second region consists only of text. The method of claim 1,
The first area includes an area within a first range from each of a leading edge and a trailing edge in the transport direction of the print medium and an area within a second range from both edges in the width direction of the print medium. The method of claim 1,
The heating member includes a first heat source for heating both end portions of the heating member and a second heat source for heating a central portion between the opposite end portions, and the temperature sensor measures the temperature of any one of the two end portions a first temperature sensor for sensing, wherein the print medium includes a third area and a fourth area fixed by the both end portions,
The processor is
When the distribution of images for the third region, which is an outer region than the fourth region, is lower than a predetermined reference, a target temperature of the distal end lower than a second set temperature at which normal fixing is possible for the third region and the fourth region is determined. and controlling the power supplied to the first heat source so that the temperature of the second point sensed by the first temperature sensor becomes the set target temperature of the distal end. 9. The method of claim 8,
The processor is
and setting the target temperature of the distal end to be lower as the distribution of the image in the third region is lower. 9. The method of claim 8,
The processor is
and controlling the power supplied to the first heat source by supplying power to the first heat source based on the second set temperature according to the print job command, and then setting the target temperature of the distal end. 9. The method of claim 8,
The processor is
if there is an image for the third region, set the end target temperature as the first end target temperature;
When there is no image for the third region, if there is an image for the fourth region, the end target temperature is set to a second end target temperature lower than the first end target temperature, and if not, the end target temperature is set to the second and setting the third end target temperature lower than the second end target temperature. 9. The method of claim 8,
When the temperature sensor further includes a second temperature sensor for sensing the temperature of the third point of the central part, and the print medium further includes a fifth area fixed by the central part,
The processor is
When the distribution of the image for the fifth region is lower than a predetermined standard, a central target temperature lower than a third set temperature at which normal fixing is possible is set for the fifth region, and the second temperature sensor sensed A fixing device for controlling the power supplied to the second heat source so that the temperature of the third point becomes the set target temperature of the central part. 9. The method of claim 8,
The processor, when there is an image for the third area,
If the coverage of the image for the third region is equal to or greater than the fourth reference value or the image for the third region does not consist of only text, the end-end target temperature is set as a fourth end-end target temperature, and and when the coverage of an image is less than the fourth reference value or the image for the third region consists only of text, setting the end target temperature to a fifth end target temperature lower than the fourth end target temperature. 9. The method of claim 8,
The processor is
If there is no image for the third area,
If there is an image for the fourth region, if the coverage of the image for the fourth region is equal to or greater than the fifth reference value or the image for the fourth region does not consist of only text, the end target temperature is set to the sixth end target temperature , and when the coverage of the image for the fourth region is less than the fifth reference value or the image for the fourth region consists only of text, the end target temperature is set to the sixth end target temperature, and the seventh end target temperature is lower. set to,
and if there is no image for the fourth region, setting the end target temperature to an eighth end target temperature lower than the seventh end target temperature. setting a target temperature lower than a first set temperature at which normal fixing is possible for the entire area of the print medium when the distribution of images in the first area, which is a predetermined outer area of the print medium, is lower than a predetermined standard; and
controlling the power supplied to the heating member so that the temperature of the first point sensed by a temperature sensor sensing the temperature of the first point of the heating member of the fixing unit becomes the set target temperature;
A method of controlling the temperature of the fixing unit comprising a.

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